Shockproof contactor



Oct. 9, 1962 L. A. FERK ET AL SHOCKPROOF CONTACTOR 3 Sheets-Sheet 1 Filed May 6, 1959 m. 6 ON 3 N fl INVENTORS' LAWRENCE A. FERK CLARENCE W. KuHN BY ATTORNEY Oct. 9, 1962 L. A. FERK ET AL SHOCKPROOF CONTACTOR 5 Sheets-Sheet 2 Filed May 6, 1959 INVENTORS LAWRENCE A.'FEFK CLARENCE. W. Kurm BY Rain, ATTORNEY Oct. 9, 1962 L. A. FERK ET AL SHOCKPROOF CONTACTOR Filed May 6, 1959 5 Sheets-Sheet 5 llllllliillllll lllll\llllllllll INVENTORS' LAWRENCE. A FERK CLARENCE W. KUHN BY 1/? R421,

A-r-roamax United States Patent i enemas SHQCKPRUGF CUNTACTGR Lawrence A. Ferk, Milwaukee, and Clarence W. Kuhn, Wauwatosa, Wis, assignors to Cutler-Hammer, inc, Milwaukee, Wis, a corporation of Delaware Filed May 6, 1959, Ser. No. 811,327 13 Claims. (Cl. 200103) This invention relates to electromagnetic switches especially designed for actuation by alternating current which meet high shock tests.

One object of the present invention is to provide such a switch which is compact and less expensive.

Another object is to minimize or eliminate magnetic hum and noisy contactor magnets.

The first object is accomplished by providing a shock resistant assembly or linkage that interconnects two armature assemblies identical in configuration and weight so that their masses act equally and oppositely to cancel shocks and also furnishes the support or mount for the armatures. This eliminates the separate armature mounting piece currently found in the art and thereby cuts the cost of the device and cuts its space requirements.

The second object is attained by using two movable armatures of identical configuration which have inner legs operating within the core of the induction coil and two outer legs overlapping the outside of the coil to eliminate air gaps at the ends of the coil and magnetic forces acting perpendicularly to the direction of the principal magnetic forces. The return springs are placed so that their force acts on a line with and in the direction of action of the principal magnetic forces. The contact operating links are oriented about the armatures and induction coil to also eliminate net forces acting perpendicularly to the direction of the principal magnetic forces.

Other objects and advantages will be pointed out in, or be apparent from, the specification and claims as will obvious modifications of the single embodiment shown in the drawings in which:

FIG. 1 is a view in end elevation of a switch assembly embodying this invention with portions broken away to show the means for holding the coil;

FIG. 2 is a sectional view taken on line 2-2 of FIG. 1 with the coil de-energized;

*FIG. 3 is a top plan view of such assembly;

FIG. 4 is a sectional view similar to that of FIG. 2

with the coil centrally sectionalized and showing the position of the armatures when the coil is energized;

FIG. 5 is an enlarged fragmentary view of the shockproof mounting mechanism and linkage in a de-energized position;

FIG. 6 is a view similar to that of FIG. 5 showing the position when the coil is energized;

FIG. 7 is an enlarged fragmentary view of the coil and movable armatures, the solid line showing the position of the armatures when the coil is de-energized, and the dotted lines showing the intermediate and final positions of the armatures when the coil is energized; and

FIG. 8 is a view of the armature assembly in perspective.

Referring to the drawings by reference numerals, the switch includes two contact assemblies 10 completely assembled and mounted in housings from which project operating plungers 12. The internal characteristics of these contact assemblies are not elements of this invention and hence are not shown or described. It is important to mount the assemblies so that the operating plungers 12 are evenly oriented about the electromagnetic assembly as shown and are movable in a direction parallel to the direction of action of the principal magnetic forces. However, each assembly includes a cover 14 which is provided with a coil-holding opening 16 to locate 3,057,980 Patented Oct. 9, 1962 and hold the coil as hereinafter described. The opening 16, shown as rectangular, may have a special configuration to assure assembly of the coil in only the proper position thus simplifying assembly techniques. The switch assemblies are held by screws to the sides 18 of a pair of spaced members forming the support for the armature carrying, shock resistant linkages, thus constituting part of the switch frame and holding the linkage in proper place.

The armature carrying, shock resistant linkages are identical and only one will be described in detail. Such linkage (best seen in FIGS. 5 and 6) consists of two spaced levers 2t pivoted on pins 22 to the wall 24 of the supporting member. The end portions of such levers are offset and a pair of armature carrying links 26 and 28 are pivotally mounted to such end portions by pins 30 as shown. The links are identical but oppositely positioned. Each link has an end lug 32 and a spring carrying lug 34 having a spring guide finger 36. A compression spring 38 :mounted between the lugs 34 urges the assembly to the position shown in FIG. 5 with the end lugs 32 in abutting relation to the lugs 34. This is also the electromagnetically de-energized position. Each link has spaced slots 49 and 42 of unequal length which hold the armatures as hereinafter explained.

The shock absorbing linkage just described (1) movably supports and (2) interconnects opposed armatures 44 and 46 which are of identical weight and configuration. Thus if a mechanical shock force is created by say quick acceleration or deceleration of the switch in one direction as a unit the forces generated in both armatures will be counterbalanced by such linkage and there will be no relative movement of the armatures and no tendency to open or close the switch or lessen contact engagement pressure. Each armature (see FIG. 8) has identically shaped side plates 48 provided with projections 50 and 52 which fit into the slots 40 and 42 when the armatures are properly oriented. The side plates are arranged face toward face so that the projections are on opposite ends. Thus the linkage guides and supports the armatures and also urges them to the de-energized position shown in FIG. 2. The movement of the armature is transmitted to the switch operating plungers 12 by connector brackets 54 mounted on tabs 56 also carried by the side plates 48. The brackets 54 have lateral arms 58 and 60 with slotted ends engaging notches on such plungers.

The movement of the armatures 44 and 46 toward each other against the force of spring 38 and into electromagnetically sealed engagement is brought about by the energization by alternating current of a coil 62 of conventional design encapsulated in an insulating coating which has projections 64 which fit into the coil-holding openings '16 in the covers 14 as heretofore described to rigidly mount the coil with respect to the armature carrying, shock resistant linkage and the armatures. The coil core is oriented parallel to the shock-proof mounting linkages and to the operating plungers 12.

In order to eliminate, or materially lessen, magnetic hum and chatter the laminated armatures 44 and 46 are of identical E-shaped design. Each has an inner leg 16 which loosely slides in the core of the coil 62 and two outside legs 68 which extend along the outside of the coil. When energized the ends of the legs 68 of the oppositely facing armatures are in surface-to-surface engagement to establish magnetic paths passing through the core and around the outside of the coil. This continuous path eliminates the conventional air gaps at the ends of the coil and does away with magnetic forces acting perpendicularly to the direction of the principal magnetic force (axially of the coil core). This prevents the breaking of the seal at such leg end faces and thus aids in eliminating magnetic hum.

In operation of the switch, energization of the coil 62 sets up fields of magnetic forces which draw both armatures 44 and 46 together against the force of the compression springs 38. The armatures move in even increments of acceleration as compelled by the shock linkages. During this controlled and guided movement the armatures move laterally through the paths shown in FIG. 7. However, there is enough clearance in the core of the coil to accommodate such lateral movement. This axial movement is transmitted to the switch assembly plungers 1 2 which move parallel to the principal line of movement of the armatures, the slotted ends of arms 6%) permitting the necessary relative lateral movement. This eliminates possibilities of binding and permits use of less armature metal and still obtains sufficient operating force. These features are additional to the shock absorbing feature previously described. Thus the use of the linkage herein described serves a dual purpose and thereby eliminates bulky and expensive separate armature mounting plates, resulting in compactness and reduction of expense.

We claim:

-1. An electromagnetic switch having a shock-proof armature suspension comprising, oppositely facing spaced mounting members, spaced pins carried on each member, levers rotatably mounted on said pins, parallel links pivotally interconnecting said levers at points equidistant from said pins, spring means mounted between parts of said links to resiliently urge said links to de-energized position, at least one slot in each link, two oppositely facing armatures having projections mounted in the slots of links on opposite mounting members, and a single coil electromagnetically affecting both armatures when energized.

2. An electromagnetic switch according to claim 1 in which each link has a pair of longitudinal slots of unequal length and the projections on said armatures are substantially the same as said slots whereby the armatures may only be assembled when properly positioned.

3. An electromagnetic shock-proof switch comprising an open ended boxlike frame of symmetrical characteristics formed by oppositely positioned armature mounting bases forming a first set of opposite sides, oppositely positioned contact assemblies secured to said bases and forming a second set of opposite sides, a coil having a core rigidly mounted between said contact assemblies, armature mounting means on said mounting biases, a pair of oppositely facing armatures identical in configuration and weight mounted on said mounting means for movement into and out of the coil core, switch actuating plungers in said contact assemblies, and connection means between said armatures and plungers.

4. An electromagnetic switch comprising a frame having spaced apart parallel wal-ls, switch units having external operators and mounted on the longitudinal margins of said frame walls in straddling, perpendicular relation thereto, an electromagnetic coil mounted centrally between said switch units, a pair of like, oppositely facing armatures, shock-proof linkages mounted on said walls affording sole support for said armatures and conraining them to movement in set paths relative to each other and said coil, and operating connections between said armatures and said external operators of said switches. v

5. The electromagnetic switch according to claim 4 wherein each shock-proof linkage comprises a pair of levers centrally pivotally mounted on a frame wall in spaced apart relation, and links interconnecting corresponding ends of said levers and afforded equal and opposite movement when said levers are pivotally oscillated, and wherein said armatures are carried by said links.

6. The electromagnetic switch according to claim 5 wherein said links of each shock-proof linkage are provided with interengageable abutments to limit their movement, and wherein a spring is carried on corresponding abutments of cooperating links to bias said links to move said armatures to spaced apart positions.

7. The electromagnetic switch according to claim 6, wherein the link abutments are transversely extending lugs, and wherein said corresponding abutment lugs engage with another lug of the other link to establish the spaced apart positions for said armatures.

8. The electromagnetic switch according to claim 5, wherein said links are provided with slots and said armatures have side extending plates with projections interfitting with said slots to mount them to said links.

9. The electromagnetic switch according to claim 8, wherein members secured to said side plates connect said armatures to the external operators of said switches.

10. An electromagnetic switch to meet high mechanical shock conditions comprising, a frame having spaced apart parallel walls, switch units mounted on the longitudinal sides of said frame walls in straddling perpendicular relation thereto, each of said switch units having at least two operating plungers which extend from opposite ends thereof and on opposite sides of a central axis lying between and extending parallel with the opposing faces of the frame walls and the opposing faces of said switch units so that an equal number of operating plungers lie on opposite sides of a plane containing said central axis and an equal number of operating plungers extend from said switch units on opposite sides of a plane perpendicular to said central axis, an electromagnetic coil having an open core whose axis is substantially coincident with said central axis, a pair of like, oppositely facing armatures, shock opposing linkages pivotally mounted on said frame walls on which said armatures are mounted and constricted in their movement with respect to said coil and each other, connections between one of said armatures and the switch operating plungers lying on one side of said plane perpendicular to said central axis, and connections between the other of said armatures and the switch operating plungers lying on the opposite side of such plane.

11. The electromagnetic switch according to claim 10 in which said connections include a member carried by each armature and having lugs extending perpendicular of said central axis and having slotsformed in the ends thereof in which portions of said operating plungers interfit with accommodation for necessary lateral movement of the armature with respect to its associated operating plungers.

12. In an electromagnetic switch, a frame having spaced apart parallel walls, a pair of enclosed switch units removably secured to the longitudinal margins of said walls in straddling perpendicular relation thereto, said switch units having openings formed in the opposing walls thereof, an electromagnetic operating coil having insulated projections interfitting with said openings in said switch units to afford secured positioning of said coil and ready removal thereof upon removal of one of said switch units from said frame.

13. The combination according to claim 12, wherein said coil is encapsulated in a molded insulating material with said projections formed therein.

References Cited in the file of this patent UNITED STATES PATENTS 2,444,157 Dries June 29, 1948 2,451,323 Doane Oct. 12, 1948 2,462,482 Evans Feb. 22, 1949 2,523,369 Jeffrey Sept. 26, 1950 2,546,053 Zirnrner Mar. 20, 1951 2,561,450 Russell July 24, 1951 2,675,443 Wyckoff Apr. 13, 1954 2,792,469 Callaway May 14, 1957 

